<!--
 * @Description: This is a JS program !
 * @Author: 史志龙
 * @Github: https://github.com/szl-shalom/
 * @Date: 2019-08-09 09:02:05
 * @LastEditors: 史志龙
 * @LastEditTime: 2019-08-09 10:07:56
 -->
<!doctype html>
<html lang="en">

<head>
	<meta charset="UTF-8">
	<meta name="Generator" content="EditPlus®">
	<meta name="Author" content="">
	<meta name="Keywords" content="">
	<meta name="Description" content="">
	<title>Document</title>
</head>

<body>

	<div id="box"></div>
	a + b = 11
	<script>


		//var username;
		//	username = box.innerHTML;
		//console.log(typeof username);



		//console.log(typeof Number("qweqwe"))
		//console.log(typeof String("NaN"))



		// console.log(Number("hello"))


		//console.log(typeof Boolean("QWRERTYE"))



		var a = 1,
			b = 1;

		document.body.innerHTML = `a + b = ${a + b.toString()}`





	</script>
</body>

</html>